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Title: Superconducting order parameter in nonmagnetic borocarbides RNi₂B₂C (R=Y, Lu) probed by point-contact Andreev reflection spectroscopy

Abstract

We report on the measurements of the superconducting order parameter in the nonmagnetic borocarbides LuNi₂B₂C and YNi₂B₂C. Andreev conductance spectra are obtained from nanoscale metallic junctions on single crystal surfaces prepared along three major crystallographic orientations: [001], [110], and [100]. The gap values extracted by the single-gap Blonder-Tinkham-Klapwijk model follow the theoretical predictions as a function of temperature and magnetic field and exhibit a small anisotropy with no indication of proposed gap nodes along the [100] and [010] directions. These observations are robust and reproducible among all the measurements on two different sets of LuNi₂B₂C crystals and one set of YNi₂B₂C crystals. We suggest that the possible gap nodes in the [100] direction may be masked by two effects: different gap anisotropy across multiple Fermi surfaces, as reported in the recent photoemission spectroscopy, and the large tunneling cone. Our results provide a consistent picture of the superconducting gap structure in these materials, addressing the controversy particularly in the reported results of point-contact Andreev reflection spectroscopy.

Authors:
; ; ; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1100118
Resource Type:
Publisher's Accepted Manuscript
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Volume: 83 Journal Issue: 10; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society
Country of Publication:
United States
Language:
English

Citation Formats

Lu, X., Park, W. K., Yeo, S., Oh, K.-H., Lee, S.-I., Bud’ko, S. L., Canfield, P. C., and Greene, L. H. Superconducting order parameter in nonmagnetic borocarbides RNi₂B₂C (R=Y, Lu) probed by point-contact Andreev reflection spectroscopy. United States: N. p., 2011. Web. doi:10.1103/PhysRevB.83.104519.
Lu, X., Park, W. K., Yeo, S., Oh, K.-H., Lee, S.-I., Bud’ko, S. L., Canfield, P. C., & Greene, L. H. Superconducting order parameter in nonmagnetic borocarbides RNi₂B₂C (R=Y, Lu) probed by point-contact Andreev reflection spectroscopy. United States. doi:10.1103/PhysRevB.83.104519.
Lu, X., Park, W. K., Yeo, S., Oh, K.-H., Lee, S.-I., Bud’ko, S. L., Canfield, P. C., and Greene, L. H. Fri . "Superconducting order parameter in nonmagnetic borocarbides RNi₂B₂C (R=Y, Lu) probed by point-contact Andreev reflection spectroscopy". United States. doi:10.1103/PhysRevB.83.104519.
@article{osti_1100118,
title = {Superconducting order parameter in nonmagnetic borocarbides RNi₂B₂C (R=Y, Lu) probed by point-contact Andreev reflection spectroscopy},
author = {Lu, X. and Park, W. K. and Yeo, S. and Oh, K.-H. and Lee, S.-I. and Bud’ko, S. L. and Canfield, P. C. and Greene, L. H.},
abstractNote = {We report on the measurements of the superconducting order parameter in the nonmagnetic borocarbides LuNi₂B₂C and YNi₂B₂C. Andreev conductance spectra are obtained from nanoscale metallic junctions on single crystal surfaces prepared along three major crystallographic orientations: [001], [110], and [100]. The gap values extracted by the single-gap Blonder-Tinkham-Klapwijk model follow the theoretical predictions as a function of temperature and magnetic field and exhibit a small anisotropy with no indication of proposed gap nodes along the [100] and [010] directions. These observations are robust and reproducible among all the measurements on two different sets of LuNi₂B₂C crystals and one set of YNi₂B₂C crystals. We suggest that the possible gap nodes in the [100] direction may be masked by two effects: different gap anisotropy across multiple Fermi surfaces, as reported in the recent photoemission spectroscopy, and the large tunneling cone. Our results provide a consistent picture of the superconducting gap structure in these materials, addressing the controversy particularly in the reported results of point-contact Andreev reflection spectroscopy.},
doi = {10.1103/PhysRevB.83.104519},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 10,
volume = 83,
place = {United States},
year = {2011},
month = {3}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1103/PhysRevB.83.104519

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Cited by: 10 works
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